Afr on idle with Greys?
12-09-2013, 11:30 AM
#5
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02-01-2014, 04:28 PM
#10
Norris Motorsport
12 - 12.5 :1 AFR at warm idle is usually the best AFR to give stable idle when using 403's.
Due to the dreadfull spray pattern of 403's the vast majority of YB engines have a very lumpy idle when trying to idle at anything near lambda 1. (14.7 :1)
A very healthy engine with std cams will usually be ok at around 13.0:1 with 403's, but in general best to run them slightly richer to ensure a good quality idle.
Remember this is only at idle folks and will cause no harm to the engine at all!
Due to the dreadfull spray pattern of 403's the vast majority of YB engines have a very lumpy idle when trying to idle at anything near lambda 1. (14.7 :1)
A very healthy engine with std cams will usually be ok at around 13.0:1 with 403's, but in general best to run them slightly richer to ensure a good quality idle.
Remember this is only at idle folks and will cause no harm to the engine at all!
02-01-2014, 04:43 PM
#11
12 - 12.5 :1 AFR at warm idle is usually the best AFR to give stable idle when using 403's.
Due to the dreadfull spray pattern of 403's the vast majority of YB engines have a very lumpy idle when trying to idle at anything near lambda 1. (14.7 :1)
A very healthy engine with std cams will usually be ok at around 13.0:1 with 403's, but in general best to run them slightly richer to ensure a good quality idle.
Remember this is only at idle folks and will cause no harm to the engine at all!
Due to the dreadfull spray pattern of 403's the vast majority of YB engines have a very lumpy idle when trying to idle at anything near lambda 1. (14.7 :1)
A very healthy engine with std cams will usually be ok at around 13.0:1 with 403's, but in general best to run them slightly richer to ensure a good quality idle.
Remember this is only at idle folks and will cause no harm to the engine at all!
A qualified answer
02-01-2014, 05:22 PM
#12
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Awsome..... I had the same question with mine which idles at around 13.5:1, which idles reasonably well.
Karl, need to book the car back in with you for a setup please.... you busy?!
Huw
Karl, need to book the car back in with you for a setup please.... you busy?!
Huw
02-01-2014, 05:38 PM
#14
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02-01-2014, 05:41 PM
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02-01-2014, 05:48 PM
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02-01-2014, 05:54 PM
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02-01-2014, 09:14 PM
#20
Norris Motorsport
Yes the weber IAW ecu's are old but a more modern ecu does'nt help with bosch 403's. They have a very shallow angle pencil spray pattern, which means the atomisation of the fuel is very poor.
If you monitor HC levels at idle when using 403's they are lowest when running the engine slightly richer. (i.e. around 12.5:1) It's quite evident in the engine tone too, with a noticably lumpy sounding idle as you lean the idle off towards 14.7:1.
This issue is not evident at all with Siemens 3102 injectors which have the same flow rate as 403's.
If you monitor HC levels at idle when using 403's they are lowest when running the engine slightly richer. (i.e. around 12.5:1) It's quite evident in the engine tone too, with a noticably lumpy sounding idle as you lean the idle off towards 14.7:1.
This issue is not evident at all with Siemens 3102 injectors which have the same flow rate as 403's.
03-01-2014, 08:35 AM
#23
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Yes the weber IAW ecu's are old but a more modern ecu does'nt help with bosch 403's. They have a very shallow angle pencil spray pattern, which means the atomisation of the fuel is very poor.
If you monitor HC levels at idle when using 403's they are lowest when running the engine slightly richer. (i.e. around 12.5:1) It's quite evident in the engine tone too, with a noticably lumpy sounding idle as you lean the idle off towards 14.7:1.
This issue is not evident at all with Siemens 3102 injectors which have the same flow rate as 403's.
If you monitor HC levels at idle when using 403's they are lowest when running the engine slightly richer. (i.e. around 12.5:1) It's quite evident in the engine tone too, with a noticably lumpy sounding idle as you lean the idle off towards 14.7:1.
This issue is not evident at all with Siemens 3102 injectors which have the same flow rate as 403's.
Agree totally Karl, mine on Greys is so lumpy on idle, can't wait to get it setup again with new injectors etc tbh.
Yes you'll need a map
03-01-2014, 11:12 AM
#26
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